System and functional tests are performed on SoC assemblies. For example, tests are performed to determine per part voltage scaling, to perform Radio-Frequency (RF) testing, to screen for specific use cases (low power modes, performance, etc.), and to reduce defective parts per million units produced, and the like. Many of such tests involve a functional test boot, in which the SoC is booted with instructions from boot Read-only Memory (ROM), a specific test case is downloaded to and executed from SoC internal memory, and the test case result is sent to ATE for evaluation.
Some existing ATE functional test methods require that the SoC have a specific type of memory interface, such as (but not limited to) interfaces associated with an embedded multimedia card (eMMC) and/or NAND gate flash memory (NAND FLASH). If a specific interface is used for testing, an ATE and test protocol may not be able to write a firmware test case to the internal memory in the SoC internal memory.
Use of a specific interface like eMMC or NAND FLASH may require customized boot ROM to handle test case download for ATE testing. However, developing custom boot ROM requires time and resources, developing customized boot ROM complicates and risks functional mode system boot, and failures of an SoC executing custom boot ROM connected to an ATE are difficult to debug.
Use of a specific interface also limits the test case size to the size of internal memory that test equipment can connect to, which may not be all of the memory of the SoC being tested.
In some functional test methods, the functional mode boot sequence of the SoC is not tested; rather, SoC is booted in test mode bypassing the critical mission mode boot sequence, resulting in test escapes.
Some existing ATE functional test methods may not be fully controlled by the ATE and may require handshake between the ATE and a central processing unit (CPU) and/or boot ROM during test case download and/or during the execution process. This can negatively impact test robustness and stability.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art.